1. Field of the Invention
The disclosure relates generally to remote monitoring systems and remote monitoring methods thereof, and, more particularly to remote monitoring systems and remote monitoring methods thereof capable of generating a status of ladder diagram for remotely monitoring execution status of a Programmable Logic controller (PLC) program of a machine according to logic switches and a PLC signal address relation information of the PLC program and parameter data for the machine when the machine is executing the PLC source program.
2. Description of the Related Art
Programmable logic controllers (PLC), as the core of machine operation, are widely used on machines such as machine tools for processing or testing. The PLC often set on the machine body or near the machine. The PLC programs can often be developed and designed by a ladder diagram, wherein the ladder diagram was a automatic control graphic language applied to a variety of the machines. There are multiple logic switches on the ladder and a PLC signal address relation information among the logic switches. The commercially available tools include, for example, FXGPWIN, CX-Programmer, GX Developer (Mitsubishi program ladder) and so on. When the machine is executing the PLC programs, staff of the factory may understand operation status of the execution of the PLC programs of the machine through the status of ladder diagram provided by the PLC itself, in which the status of ladder diagram is primarily combining the PLC program of the ladder diagram with parameter data on the machine to show the status of each logic switch on the ladder diagram when the PLC program is being executed. When the machine has a breakdown, staff usually check the PLC first and look at the PLC status of ladder diagram to judge the possible reason of that breakdown. In the art, current PLC status of ladder diagram only can be displayed on the machine or PLC in the factory locally. It cannot directly be provided to remote side (such as for developer of manufacturers, maintenance people to look at) so that the people on remote end cannot judge the reason for the breakdown. The status of the ladder or the machine signals usually is informed to the remote staff through the person in the factory by telephone. Otherwise the remote staff may go to the factory and look at the PLC status of the ladder and judge the reason. It is very inconvenient for debugging and more time consuming.
To solve the above problem, additional cameras or image capture device are set up on some machines to directly shoot or capture the PLC status of ladder diagram and then transmit the shot screen image to the remote side for debugging. In this kind of implementation, however, installation of exclusive software and hardware are required on the machines by the OEM controller, so that the screen image of the PLC status of ladder diagram can be transmitted to the remote side for debugging in real time. It will resulting in a high replacement cost. Meanwhile, the screen image of the PLC status of ladder diagram which is transmitted to the remote side may easily be distorted. The remote staff may only look the transmitted image and cannot select the wanted image of ladder diagram for debugging. Therefore the remote staff can not efficiently determine possible fault causes for the machine based on only the transmitted PLC status of ladder diagram.